MANUAL# 5005-2040-000-F UPDATED: 6/1/2021
17
F. Calibration of the Velocity Mode Drive (SMA5015 Series)
The Drive, in this configuration, receives an analog, bi-polar input command, which is proportional
to the motor velocity. The Drive receives velocity feedback from a tachometer, which is usually
mounted to the rear of the motor. The following pots will be set during calibration: (Note: RV7 is a
single turn pot and RV1-RV6, RV8-RV10 are 20-turn pots.)
Note: RV9 and RV10 are factory set and should not be adjusted. Adjusting these pots voids
warranty.
PROCEDURE:
1. Connect motor cables to TB1 MTR+ and MTR-. Connect the motor ground to chassis ground.
2. Connect the Tach. wires to J1-5 (TACH. INPUT) and J1-11 (COMMON).
3. Apply main power and fan power.
Visually confirm an “O” on the 7-segment display. Depending
on the configuration of the Inhibit, Reset and +/-Limits, it may be necessary to make
appropriate connections to those terminals before the Drive will be enabled and energize the
motor.
4. Slowly turn the Loop Gain (RV7) CW. Motor should be stopped or turning slowly. If the motor
starts running away, remove the power, reverse the Tach. leads, and apply power.
5. Set Balance (RV3) for zero motor rotation.
6. Set the desired peak current limit by adjusting RV6 while measuring voltage at TP6. The ratio is
1V=6A.
7. The purpose of the following procedure is to set the system bandwidth to obtain a critically-
damped response (see figure C) or a one hook overshoot response with the maximum possible
Tach. Gain. There are many possible settings of Tach. Gain and Compensation which will yield
the desired waveform: The optimum setting will occur when Tach. Gain is as CW as possible
and Compensation is as CCW as needed. However, the velocity loop may become unstable
(the motor oscillates or hums) as the Compensation is tuned CCW (increasing the BW). In this
case, stability is the limiting factor: At no time should the velocity loop be allowed to be
unstable. Drives are normally shipped with the Tach. Gain (RV4) set at 100%. This is a good
place to start. If you are unsure of where the Tach. Gain is set, turn the Tach. Gain (RV4) fully
CW (up to 20 turns).
Pots
Name of Pot
Notes
RV1
Differential Gain,
AUX
Sets the input voltage to velocity ratio for differential signal input.
RV2
Signal Gain,
SIG
Sets the input voltage to velocity ratio for single-ended signal
input.
RV3
Balance,
BAL
Used to null any offset in the system.
RV4
Tach. Gain,
TACH
Sets the DC tachometer gain.
RV5
Compensation,
COMP
Used in conjunction with Tach. Gain to set the system bandwidth.
RV6
Current Limit,
I LIMIT
Sets the maximum motor current. Shipped set CW (max).
RV7
Loop Gain,
LOOP GAIN
Used to shut off uncalibrated Drives. When the loop gain is fully
CCW, no current is delivered to the motor.
